Topical Area: Dietary Bioactive Components
Objectives : Dysbiosis of the gut microbiota (GM) is observed in both murine models and humans with cystic fibrosis (CF). Laxative treatments are typically used to improve gastric motility and alleviate gastrointestinal symptoms associated with CF. Genistein, a phytochemical in soy, exerts therapeutic benefits by activating intestinal CFTR ion channels but whether genistein affects the GM in CF is unknown. This study aimed to establish whether dietary genistein alters the GM community structure in a murine model of the most common CF-associated mutation, DF508.
Methods : In this 3-arm parallel randomized intervention, 21-day old DF508 mice (n=24) were fed standard chow (CHOW; n=11), CHOW plus Colyte (laxative; n=7), or CHOW plus 600 mg of dietary genistein (GEN) per kg of diet (n=6) for 45 days. Fecal pellets from day 45 were frozen at -80˚C and microbial genomic DNA extracted using a DNeasy PowerSoil Kit. The 16S rRNA gene was sequenced via Illumina MiSeq. Sequences were quality checked and denoised using DADA2 and taxonomy determined using the GreenGenes 13.8 database. Treatment differences in the GM were compared using both alpha (within-sample) and beta (between-sample) diversity metrics (Kruskal-Wallis and PERMANOVA tests).
Results : Both observed operational taxonomic units (OTUs) and Shannon’s diversity index (alpha diversity richness measures) were greater for CHOW (OTUs: p=< 0.003; Shannon’s: p< 0.003) and Colyte (OTUs: p=0.012; Shannon’s: p=0.006) compared to GEN animals. Colyte resulted in significantly lower species richness (OTUs: p< 0.005) compared to CHOW. Species evenness (Pielou’s) did not differ suggesting the importance of species richness over evenness for group differences. Jaccard, Bray-Curtis, unweighted and weighted UniFrac metrics (beta diversity measures) revealed significant group differences (GEN vs. CHOW: p’s< 0.004; GEN vs. Colyte: p’s< 0.005; CHOW vs. Colyte: p’s< 0.006) suggesting that differences in GM community structure were driven by presence/absence, abundance, and phylogeny of taxa.
Conclusions : Colyte and GEN resulted in lower within-sample diversity and significant differences in beta diversity compared to CHOW mice. Species abundance differences between Colyte and GEN groups and how disease prognosis is impacted require further investigation.
Funding Sources : Midwestern University intramural funds (LA) and Arizona State University internal funds (CMW).
College of Health Solutions, Arizona State University
Arizona State University
Arizona State University
Dept of Physiology, Coll of Graduate Studies & Arizona Coll of Osteopathic Medicine, Midwestern Univ